Emergency grate



July 31 1945 R. c. cRoss 2,380,630

EMERGENCY GRATE Filed OGL. 8.; 1942 2 Sheets-Sheet 2" Patented July 3l,1945 EMERGENCY GRATE Robert C. Cross, Riverside, Ill., assignor toSears, Roebuck and Co., Chicago, Ill., a corporation of New YorkApplication October 8, 1942, Serial No. 461,296

1 Claim.

This invention relates to emergency grates such as those employed inconverting oil burners to use with coal or other solid fuel burners.

The term furnace is hereinafter used for convenience to denote heatingplants generally, whether they be hot water or steam heating boilers orwarm air furnaces.

It is an object of the invention to provide a conversion grate soconstructed as to lbe usable in hea-ters or heating plants Varyingwidely in furnace chamber sizes.

A further object is to provide a plurality of interchangeablyinteriitted grate parts whereby a grate may be assembled in variousShapes and sizes and installed inany of a variety of furnace chambershapes and sizes.

An additional object is to provide a conversion grate having frangibleor severable portions enabling the grate to be reduced in size bybreaking off sections to fit a selected size of furnace chamber.

Another object is to provide a conversion grate unit constructed toenable the fuel to be burned i well beyond the re bed area of theoriginal oil burner element but instead more totally extensive with thewalls of the furnace chamber.

Further objects and advantages of the invention will appear as thedescription proceeds.

The invention will be better understood upon reference to the followingdescription and accompanying drawings in which:

Fig. 1 is a fragmentary vertical sectional view taken as indicated bythe line I-I in Fig. 2.

Fig. 2 is a plan sectional View taken as indicated by the line 2 2 inFig. 1.

Fig. 3 is a fragmentary plan view of separated complemental grate partsappearing in assembly in Fig. 2.

Fig. 4 is a vertical sectional view taken as indicated at 4 4 in Fig. 3and showing how the complemental parts may be brought into assembly.

Fig. 5 is a sectional View taken as indicated at 5-5 in Fig. 3.

Fig. 6 is a sectional view similar to Fig. 5 but shows the partsassembled.

Fig. 7 is a fragmentary plan view, similar to Fig. 2 but without thespacer or leaf, and with the parts reduced in area to t a smallerfurnace chamber.

Fig. 8 is an enlarged fragmentary sectional view taken as indicated bythe line 8-8 in Fig. 7. l

Fig. 9 is a fragmentary inverted plan View of the grate shown in Fig. 7.

Fig. 10 is an enlarged fragmentary sectional view taken as indicated bythe line I -I0 in Fig. 2.

Fig. 11 is a side elevation of the leaf inserted casting taken asindicated by the line II-II in Fig. 2.

Fig. 12 is a transverse sectional view showing a blower in aninstallation equipped with one embodiment of the invention.

Fig. 13 is an enlarged fragmentary end elevational view taken asindicated by the line I3-I3 in Fig. 2, but with certain of the partsseparated.

Fig. 14 is a view similar to Fig. 3 but of a modication.

Referring now more particularly to the drawings, the grate structure inaccordance with my invention may comprise a pair of substantiallysemicircular members I5. Each member I5 may be of stepped, cascaded orterraced formation, comprising an upper central portion I6, andcircuxnferential steps I8 of progressively increasing diameter downward,terminating at the outer periphery in a depending flange I9. The outerperipheries of the steps are selected in accordance with standardfurnace chamber dimensions, the construction being such that, as willappear, the size may be readily reduced to the desired area by the user.

For the introduction of primary air to the fuel adapted to be burnedover the grate, each grate member is provided with numerous openings.Said openings may be disposed in any desired location and arrangement,that disclosed here being illustrative. 'I'he openings 2I in therelatively horizontal portions of the steps are preferably arranged toprovide at suitable intervals bridging portions 22 having score groovesor weakening notches 24, said notches being sufficiently deep and saidportions being sufficiently short so that the user, with the aid of achisel, can readily sever each portion thus weakened, and by repeatingthis operation at every such portion yin the same circumferential seriesremove the portion outward of such series. This operation may beperformed on each grate casting or forging, whereupon the members may bereadily inserted into the users furnace and assembled over the oilburner combustion chamber (Fig. 7).

The diametral margin of each member I5 comprises two portions 28 and 29,offset from each other, both vertically and horizontally, affording arecess 3| over the portion 28, said recess terminating inwardly at awall 32 adjacent but short of the center of the member. The free edge 33of said wall 32 may be ush with the free edge 35 of the depressedportion 28 and terminates on the other side of the center a distancesubstantially equal to the distance of said recess 3l from the center,at a horizontally offset shoulder 38 forming the inner terminus of theundepressed mar ginal portion or lip 29. The free edge 39 of the lip 29and the side wall 4I of the depression 3I are disposed on opposite sidesof and equi-distant from the diametral plane containing the edges 33 and35.

A hole 43 may be formed in one of the marginal portions, such as theportion 28, and a pin 45 formed in the lip 29. In assembling themembers, they are disposed with their diametral margins crossed (Fig. 4)in such manner that each lip 29 overlies the depressed portion 28 of thecompanion member, with the pins 45 slightly entered or disposed toreadily enter the cooperating holes 43. Then, as the members arerelatively swung to lie ush with each other, the lip 29 of each comes torest in the depression 3| of the other and the respective pins are fullyentered in the respective holes, so that the members are locked togetheras a unit operative just as though they were cast in one piece, exceptfor necessary clearance between pins and holes.

If desired, the pins 43 and holes 45 may be omitted, in which event themembers may be placed on the support in the furnace and simply slid intoassembly, the lip 29 of each member telescopically entering thedepression 28 of the other until the members are in abutment as in Figs.2 and '1.

Each member I5 may be provided with reinforcing ribs 46 reinforcing thevarious steps I8, and with additional ribs 41 reinforcing the top I6.The edge flange I9 serves the purpose among others, of preventing warpof the outer portion of the casting and affording edge reinforcementtherefor in service. i,

The openings 2l servenot only to weaken the steps I8, but to admit airfor combustion of the solid fuel supported by the grate. Additionalopenings 48 at the junctures of the steps I8 and Y openings 49 in thetop I6 are provided to insure an adequate air supply.

' Furnace retort openings and oil burner combustion chambers areconventionally round, obround, square or rectangular. The round gratejust described may be suitable for any furnace wall and combustionchamber shapes.

For an elongated furnace, or one having an elongated combustion chamber,I may provide, in addition to the aforesaid semicircular members I5,interchangeable leaves or spacers 5I of generally rectangular form, eachleaf being formed at each of its longitudinal margins with a lip 29 anda depression 3I in conformity with the aforesaid margins of thesemicircular grate members I5, the margins being interchangeable. Thusif only one such spacer is used it can be assembled with each of thesemi-circular members I5 in exactly the manner described above (Fig. 2).If two or more leaves are to be employed, it is obvious how they may bereadily assembled with one another and with the semi-circular membersl5.

It will be observed thatlike the end members I5, the spacers 5I areformed with holes 2l, 48 and 49 for admitting primary air supply andwith frangible portions 53 adapted to form continuations of the seriesof such portions 22 in the members I5, so that the spacer per.pheriesmay be broken olf in conformity with the reduction in size of the endmembers I5, whereby the spacers in assembly with the end members mayprovide a. continuous periphery. The spacers may be provided with holes43 and pins 45, or these may be cordance with my invention may beinstalled for use. To this end, I have shown a furnace combustionchamber having a wall 5S and an oil burner combustion chamber 68 whichis converted to use with solid fuel such as coal. Accordingly, the oilburner electrode-and-nozzle assembly are removed, and the oil pump andignition wiring disconnected, leaving the air tube 69 equipped with a`fan 1I for blowing primary air into the oil burner combustion chamber.Suitable heat insulation 12, such as rock wool or other material, ispacked in the space between the furnace foundation wall or ash pit 66and the oil burner combustion chamber, an annular sheet 14 of asbestos,metal, or other suitable material being applied to the top of theinsulation and oil burner combustion chamber wall to provide a Vfloor orsupport for the grate. If desired, the floor may be formed by a cementcovering over the rock Wool or other filler, and substantially flushwith the top of the oil burner combustion chamber.

The parts of the grate, reduced to the desired size if necessary, thatis, the maximum size to which it can be reduced and still fit in a givenfurnace chamber, as explained above, are then inserted through the firedoor or other suitable opening and assembled as explained above. Theassembled grate unit is then adjusted so that its periphery issubstantially uniformly spaced from the interior wall 11 of thecombustion chamber. Refractory cement or clay 18 is then applied at theperiphery of the grate to seal its juncture with the floor 14, so thatexcess leakage of primary air from the plenum space 19 beneath the gratewill be precluded and at the same time the grate will be retained in thedesired position. If the grate is not reduced, its depending peripheralflange I9 will rest on the floor 14 as shown in Fig. l. If the grate isof reduced size lFigs. 7 and 8), the outermost horizontal portion 83 ofthe grate may be spaced from the door 14 by the depression 28 and pins85, Fig. 9, formed on the bottoms of the steps, the bottoms of the pinsbeing in the same planes as the respective bottom surfaces of thedepression 28 formed on the same member.

1n use, solid fuel such as coal is fed onto the grate, and inasmuch asthe grate has openings therethrough substantally to the outer peripherythereof, the primary air blown in by the fan will mushroom from the topof the oil burner cornbustion chamber, and reach all of the coal on thegrate through said openings and thus all of the coal on the grate willbe burned evenly. Accordingly, my invention affords in effect a plenumchamber extending a substantial distance laterally beyond the rim of theoil burner combustion chamber.

This is a substantial improvement over past grates in this respect, suchgrates providing for the burning of only that portion of the coal whichis directly over the oil burner combustion chamber.

The two end members being identical, and

therefore interchangeable, and the same being true for the spacers, andin view of the formation of the parts which adapts them to form units tot various sizes of furnace Walls, it is apparent that I have provided aconversion grate con struction of extremely low cOst which makes it asimple and inexpensive matter in .a time of economic shortage, toconvert oil burners to solid fuel burners. Y

For reconversion to oil burning, it is an easy matter to remove therefractory, separate and remove the grate parts and Ireinstall the oilburner apparatus.

Various modications coming Within the spirit of my invention may suggestthemselves to those skilled in the art, and hence I do not wish to belimited to the specic form shown or uses mentioned, except to the extentindicated in the appended claim, which is to be interpreted as broadlyas the state of the art will permit.

I claim:

A solid fuel conversion grate, comprising a pair of semi-circularcastings, each having two edge formations oppositely offset from adiametral line `constituting a median junction between said castings andmeeting at a midpoint of said line, one of said edge formations of eachcasting being throughout recessed to receive the non-recessed edgeformation of the other of said castings during intertting placement ofsaid castings one with the other, a series of cascaded semi-circularsections integral with each of said castings having progressively largerdiameters and progressively loWer planes in horizontal correspondence,said edge formations defining said cascaded sections,

v and an optionally insertible intermediate casting having edgeformations complementary to those of its adjacent semi-circular castingand correspondingly oiset so as to afford elongation to said conversiongrate in a direction transverse of said diametral line.

ROBERT C. CROSS.

